possible to downsample music/sound in Jet Grind Radio?

[hrb2k]

is it possible to downsample the music/sound/voices in jet grind radio. if so, what are some of the tools i might need.

i like to put more than one backup game on a cd and jgr is 570MB big. i want to downsample some files so that i can fit at least 2 games on one cd.

so is it possible to downsample the music and which files are they?